1. Field of the Invention
This invention pertains generally to material or article handling, and more particularly to a pipe handler such as might commonly be used in the oil drilling and rigging industry to assist with the handling of very large and heavy pipes that are regularly raised to and lowered from an elevated drilling platform.
2. Description of the Related Art
In the oil drilling and rigging industry, drilling platforms commonly referred to as derricks are assembled above the earth. These derricks facilitate the drilling and installation of wells. The platform or work floor typically may be elevated many feet above the ground.
Drill strings of very large and heavy pipes are assembled or disassembled on the derrick. For exemplary and non-limiting purposes, these pipes may be stored horizontally on or near the ground adjacent to the derrick. This means that these very large and heavy pipes must be re-oriented from horizontal to more nearly vertical orientation, and raised from near ground level to several tens of feet into the air. Consequently, the handling of these large and heavy pipes is not suited to manual labor, and instead requires mechanical assistance.
Pipe handlers are commonly be used to assist with the handling of these very large and heavy pipes that are regularly raised and lowered from an elevated drilling platform. A large number of patents are exemplary of this technology, and provide the background for the basic features, while also contrasting with the novel features of the present invention. These U.S. patents, the contents and teachings which are incorporated herein by reference, include: U.S. Pat. No. 2,643,006 by King, entitled “Automatic pipe handler,” that illustrates an early automatic pipe handler, and describes a bumper or stop having a resilient portion in the form of a rubber or spring against which the drill pipe may abut, that prevents a pipe section from sliding down the dolly. U.S. Pat. No. 3,792,783, entitled “Pipe Handling System” and U.S. Pat. No. 3,916,500 entitled “Pipe handling apparatus”, each by Cicero C. Brown, the contents and teachings which are incorporated herein by reference, describe another early automatic pipe handler having an endless cable or chain driving a lug to elevate a pipe in a trough to push the pipe toward the derrick. This same lug is also used to control the rate of descent of the pipe. U.S. Pat. No. 4,386,883 by Hogan et al, entitled “Materials lifting apparatus” and U.S. Pat. No. 4,494,899 by Hoang et a1, entitled “Pipe trough for transporting pipe between upper and lower positions”, the contents and teachings which are incorporated herein by reference, each describe automatic pipe handlers with kickers to assist with the loading and unloading of pipes. Hogan refers to these kickers as pipe ejecting assemblies that eject the pipe from the carriage using an arm and a ram, and Hoang et al refers to these as unloading arms for ejecting the pipe from the trough. Hoang et al also describe pipe loading arms to assist with loading pipe into the trough. U.S. Pat. No. 4,235,566 by Beeman et al, entitled “Pipe-conveying catwalk” and U.S. Pat. No. 4,439,091 by Frias, entitled “Pipe feeding system”, the contents and teachings which are incorporated herein by reference, each illustrate carriages that move along a trough. The teachings and content of U.S. Pat. No. 3,559,821 by James, entitled “Drill Pipe Handling Apparatus” and which illustrates another drill pipe handling apparatus, is additionally incorporated herein by reference.
Additional U.S. patents illustrating various kicker constructions, the teachings and contents which are incorporated herein by reference, include: U.S. Pat. No. 4,140,227 by Beck, entitled “Cable way apparatus for transporting pipe”; and U.S. Pat. No. 4,403,898 by Thompson, entitled “Pipe pick-up and laydown machine”. Additional patents showing rigid pipe handler structures, the teachings and contents which are incorporated herein by reference, include: U.S. Pat. No. 2,880,881 by Robishaw, entitled “Unitized pipe rack”; U.S. Pat. No. 2,958,430 by Robishaw, entitled “Pipe rack and lay-down trough”; U.S. Pat. No. 4,684,314 by Luth, entitled “Pipe handling apparatus”; U.S. Pat. No. 6,079,925 by Morgan et al, entitled “Method and apparatus for lifting oilfield goods to a derrick floor”; U.S. Pat. No. 7,635,249 by Guidroz, entitled “Pipe pick-up and laydown apparatus”; U.S. Pat. No. 7,665,944 by Guidroz, entitled “Pipe pick-up and laydown apparatus and method”; U.S. Pat. No. 7,992,646 by Wright et al, entitled “Horizontal offline stand building system”; and U.S. Pat. No. 8,052,368 by Littlewood et al, entitled “Catwalk for a drilling rig”. Other relevant patents and published applications, the teachings and contents which are incorporated herein by reference, include: U.S. Pat. No. 6,899,510 by Morelli et al, entitled “Pipe handling system for presenting sections of pipe to a derrick work floor having a pipe ejection assembly”; U.S. Pat. No. 7,021,880 by Morelli et al, entitled “Pipe handling apparatus for presenting sections of pipe to a derrick work floor having a high-speed carriage assembly”; U.S. Pat. No. 7,163,367 by Handley, entitled “Multi-position height adjustment system for a pipe handling apparatus”; and 2008/0263990 by Morelli et al, entitled “Skidding system for a catwalk”. The Handley patent illustrates one technique for adjusting the height of the boom on an automatic pipe handler. In Handley, a plurality of boom ports and arm ports are provided, and one boom port is linked to one arm port through a hinge pin. The particular selection made by the hinge pin determines the height of the boom.
From these foregoing patents, the basic structure of a pipe handler and the function thereof will be well understood. In addition to the foregoing patents, Webster's New Universal Unabridged Dictionary, Second Edition copyright 1983, is incorporated herein by reference in entirety for the definitions of words and terms used herein.